An End-to-End Approach to Host Mobility

We present the design and implementation of an end-to-end architecture
for Internet host mobility using dynamic updates to the Domain Name
System (DNS) to track host location. Existing TCP connections are
retained using secure and efficient connection migration, enabling
established connections to seamlessly negotiate a change in endpoint
IP addresses without the need for a third party. Our architecture is
secure-name updates are effected via the secure DNS update protocol,
while TCP connection migration uses a novel set of Migrate
options-and provides a pure end-system alternative to routing-based
approaches such as Mobile IP.

Mobile IP was designed under the principle that fixed Internet hosts
and applications were to remain unmodified and only the underlying IP
substrate should change. Our architecture requires no changes to the
unicast IP substrate, instead modifying transport protocols and
applications at the end hosts. We argue that this is not a hindrance
to deployment; rather, in a significant number of cases, it allows for
an easier deployment path than Mobile IP, while simultaneously giving
better performance. We compare and contrast the strengths of
end-to-end and network-layer mobility schemes, and argue that
end-to-end schemes are better suited to many common mobile
applications. Our performance experiments show that handoff times are
governed by TCP migrate latencies, and are on the order of a
round-trip time of the communicating peers.

NB: This version has a slightly altered version of Figure 1. The previous version, while technically correct, appeared to require the wrapping of sequence spaces between packets three and four, which may have lead to some confusion.